The present invention relates to a process and a device for producing protective elements for the electronic protection of objects, wherein the protective elements consist of at least two layers, as well as to an appropriate tape material.
Goods in department stores and warehouses are electronically protected against theft in increasing numbers. A possibility of electronic theft protection consists in attaching strip elements, i.e. elongated metal pieces of low magnetic retentivity (for example VITROVAC of the firm Vacuumschmelze), to the goods. These strip elements trigger an alarm in appropriate monitoring systems, which customarily are arranged in the exit area of the protected establishment.
The electronic protection of objects can be roughly described as follows: a monitoring system has a transmitting and a receiving device. The transmitting device transmits an interrogation signal into a monitoring zone. The strip element is induced to send out a response signal, which is detected and identified by a receiving device. The appearance of the response signal is equated to the unauthorized passage of an electronically protected article through the interrogation zone, and the alarm is triggered. An example of a corresponding monitoring system is described in European Patent EP 0 123 586 A1.
Besides strip-shaped protective elements for so-called electromagnetic protection of objects, resonance protective elements are also employed. These resonance protective elements consist of a resonant circuit with capacitive and inductive elements. As soon as such a resonant circuit is subjected to an electromagnetic field within an interrogation zone, it transmits a response signal at its resonance frequency.
An object of the present invention is to provide a cost-effective, simple process, an appropriate device and a tape material, which can be produced by means of the process, for the electronic protection of objects.
In regard to the process, this object is attained in that sections of a predetermined length of a second material web are fed to a first continuous material web transversely to the running direction of the first material web, and are applied. An exemplary embodiment of tape materials produced in this manner will be cited.
The previously mentioned strip elements for the electronic protection of objects have a length of a few centimeters (for example, 3 cm). Usually labels, each containing a strip element, are made available in the form of a roll of labels and are dispensed by means of appropriate dispensing devices. If the strip elements of a few centimeter length are wound in the longitudinal direction into a roll of labelsxe2x80x94as is customaryxe2x80x94, a roll of labels contains only relatively few labels. This looks much different, if the strip elements are dispensed transversely to the dispensing direction. In this case the number of strip elements per roll of labels can be considerably increased.
The transverse arrangement of the strip elements brings particular advantages, if the way they are normally produced is taken into consideration: a relatively wide endless strip of a material of low magnetic retentivity is produced; subsequently, this endless strip is split into several, adjacently located endless strips of a material of low magnetic retentivity. Because of this it is possible without problems that a label, which has been applied from the side to the first material web already contains several parallel extending strip elements. By means of this it is possible to again considerably reduce the manufacturing costs for rolls of labels made up of strip elements.
In accordance with a further application example, sections of a thin film material (such materials are extensively described in European Patent, EP 0 295 028) are applied to an endless strip made of a thin film material. As a condition of manufacturing, these film materials have a preferred direction, i.e. the response signal is maximal if the interrogation field is aligned parallel with this preferred direction, while it is zero in the case of an impact perpendicular with the preferred direction. If now two layers of a thin film material are arranged perpendicularly with respect to each other, the corresponding protective element in the interrogation zone is always excited to transmit a response signal.
The process in accordance with the present invention is distinguished in that in accordance with an advantageous further development, the application of the sections of predetermined length of the second material web to the first material web can take place in steps or continuously. The higher production speed is of course an advantage of the continuous process.
With respect to the device in accordance with the present invention, the noted object is attained in that a guide device for a first material web is provided, that at least one dispensing device is provided, which is arranged perpendicularly in relation to the guide device and through which the sections of a predetermined length are fed to a second material web, and that a conveying device is provided, which successively receives the sections of predetermined length of the second material web from the dispensing device and fixes them to the first material web directly next to each other or spaced apart.
While with only a single dispensing device the application of the sections on the first material web takes place in steps, the continuous operation of the device in accordance with the present invention is possible starting with two dispensing devices. It is only required for this that the n dispensing devices are at a defined distance from each other, and that the sections are supplied at a speed which is matched to the running speed of the first material web. The speed with which the sections are supplied must be at least such that one section is already in the lateral end position in relation to the first material web when a pressure roller is moved down in order to fasten the section in the desired. longitudinal position on the first material web.
For the purpose of applying the sections to the first material web, in accordance with an advantageous further development of the device of the present invention, a pressure roller is provided transversely to the running direction of the first material web, which is designed to be movable up and down and presses the section of the predetermined length against the first material web as soon as the section has reached the preselected longitudinal position in relation to the first material web. The pressure roller remains placed against the first material web until the section, which adheres to the first material web, has been moved through underneath it.
So that the pressure roller is provided with the information as to when it is to be placed on the first material web, an advantageous embodiment of the device in accordance with the present invention proposes a stop or a sensor for detecting the correct lateral alignment (in relation to the first material web) of the sections of the second material web. The stop or sensor is connected with a control device, wherein the control device moves the pressure roller against the first material web as soon as the stop or sensor provides the information that the section of the predetermined length of the second material web has reached the predetermined position in relation to the first material web.
In order to be able to detect the correct longitudinal position (in relation to the first material web), the control device is connected, for example, with a further sensor, which detects registration markers on the first material web. In this connection it is also possible to synchronize the feeding of the sections with the running speed of the first material web in such a way that the sections are always automatically applied to the desired position on the first material web.
In accordance with an advantageous further development of the device in accordance with the present invention, n dispensing devices are provided, which are arranged at a spacing of (2n+1)*(b+z), wherein b describes the width of the sections of the second material web and z the desired spacing between two successive sections of the second material web. This embodiment makes it possible that the n dispensing devices can operate parallel with respect to each other, i.e. without a chronological offset. The control outlay is of course considerably reduced by this.
The advantages of the further development of the device in accordance with the present invention of calculating the running speed of the first material web in such a way, that the sections of predetermined length of the second material web are applied in a continuous process to the first material web, have already been previously mentioned.
An advantageous embodiment of the device in accordance with the present invention provides, that the conveying device is a conveyor belt, in relation to which a vacuum source has been arranged in such a way that the individual sections of predetermined length of the second material web are fixed on the conveyor belt at the desired spacing from each other. In this connection it is particularly advantageous, if the conveyor belt has air holes.
An alternative solution provides, that the conveying device is a conveyor belt, in relation to which at least one magnet has been arranged in such a way that the individual sections of predetermined length of the second material web are fixed on the conveyor belt at the desired spacing from each other. This is possible thanks to the magnetic properties of the materials used for the electronic protection of objects.
In accordance with an advantageous further development of the present invention, a storage roller is provided, on which the finished tape material is wound.
With respect to the tape material in accordance with the present invention, the object is attained in that the first material web is a continuous material web, on which sections of a second material web of predetermined length are supplied transversely to the running direction of the first material web and are applied.
An embodiment, which is advantageous in many actual uses proposes, that the first material web is a support material, and that the sections of predetermined length of a second material web are adhesive labels, each of which contains at least one protective element for the electronic protection of objects.
An alternative provides that the protection elements are a multitude of strip elements, which can or cannot be deactivated and which are arranged parallel in relation to each other and transversely in relation to the running direction of the first material web.
The following embodiment is also very advantageousxe2x80x94depending on the type of usexe2x80x94: the first material web is a thin film material, whose preferred direction extends transversely, or respectively parallel with the direction of running of the first material web, while the sections of predetermined length of the second material web are also thin film labels, whose preferred direction extends parallel, or respectively transversely in relation to the running direction of the first material web.
A further embodiment of the tape material in accordance with the invention proposes that the sections of predetermined length of the second material web are resonance labels.